The walls were not the city's strength. When the war began in 1642 Worcester's medieval defences were so dilapidated that the wooden gates, in the words of a contemporary, "would hardly shut, and if they were actually closed there was neither lock or bolt to secure them." Once the Royalists took permanent possession in November 1642, they had begun the long, expensive work of bringing the walls up to 17th-century standards: bastions added, ditches deepened, a sconce built on the summit of Castle Hill with cannon platforms below it, earthworks dug to the south. The historian J.W. Willis-Bund notes that Worcester sits in a bowl commanded by hills on either side and could never have become a real fortress - Continental engineers would have called it indefensible - but by 1646 it was at least as defensible as any English provincial town not built for war. The governor was Colonel Henry Washington, a young Royalist of restless temperament. He had 5,000 men nominally, perhaps half that in fighting trim, and a city he had already begun stripping for fuel and field of fire.

The Parliamentary commander for the first phase was Colonel Edward Whalley, sent from Oxford with cavalry to harry the garrison while the New Model Army finished other business. He arrived around 21 May 1646 and ringed the city loosely, picking off cattle, intercepting foraging parties, and bombarding from Rogers Hill and Battenhall. The investment tightened by stages. On 8 July Whalley was replaced by Colonel Thomas Rainsborough, a far more formidable figure - the New Model Army officer who would the following year argue at the Putney Debates that "the poorest he that is in England hath a life to live, as the greatest he." Rainsborough held a review of his forces on Rainbow Hill on 9 July, brought 31 carriages (10 of them ordnance) up to Barbourne House as his headquarters, and joined his works in a continuous line from Perry Wood to Red Hill Cross. Inside the city, beef was selling at 8d a pound. Sir John Knotsford paid 30 shillings for a piece of roasting beef. The magazine was opened on 8 July - a sign that fuel and food were both running short.

The most dramatic moments of the siege were not on the walls but inside the Bishop's Palace, where Washington called a council of war on 27 June after a captured Royalist named Anthony Kempson arrived with confirmation that Oxford had truly fallen. Washington wanted to treat. So did most of the moderates and the clergy. Fitzwilliam Coningsby, former Royalist Governor of Hereford and a man of property in three counties, refused absolutely. Until they heard from the King in person, he said, surrender was unthinkable. Asked whether they would stand and die with him on the walls, Coningsby replied that they would, and proposed that anyone who disagreed should be thrown over them. Washington - by all accounts a passionate man - swore a great oath, declared he would break off all negotiations and fire a gun himself, and stormed out. The bishop chased after him, caught him, and talked him into appointing a committee of six gentlemen, six soldiers, six citizens, the bishop, and Dr Warmestry to decide. The committee voted unanimously to treat.

The detail every account of this siege mentions is the cow. The besiegers, frustrated that the city's cattle were being grazed under cover of the walls, tried an ingenious cruelty: they tied a cow to a stake outside the city, built a fire around it until it bellowed in pain, and waited for the other cows to come investigate so they could cut them off from the gates. The cows did not come. The cow died. The story survives because it was unusual enough to be written down, but the casual cruelty of besieging warfare comes through unsoftened. So does the smaller suffering. On 11 July a cannonball from Rogers Hill struck the Town Hall and rolled forty yards to the Earl's post. Another hit Mr Street the Town Clerk's house. An iron saker at the Blockhouse burst, hurling a 60-pound fragment onto the Rose and Crown near St Helen's Church and others into Broad Street, wounding several people. Inside Worcester through July, civilians lived alongside increasingly indisciplined soldiers; desertion was constant; provisions would last, the governor calculated, about a fortnight.

Rainsborough's final terms arrived on 18 July - articles of surrender as final, with two days to accept. The most contentious clause specifically excluded Sir William Russell, the Royalist former governor, from the protection given to everyone else. Several officers refused to sign on his behalf, saying it was the same as consenting to his murder. Russell ended the argument himself. "He neither feared nor cared what the enemy could do unto him," he said. "He had but a life to lose, and it could not be better spent." On 23 July, the last day of the siege, an Anglican service was held in Worcester Cathedral at six in the morning. It would be the last service held there according to the rites of the Church of England for 14 years. The cathedral organ had already been taken down. Many of the gentlemen and officers attending knew it would be the last time they would hear the prayer book at all. The cathedral itself would shortly be used to store Parliamentary munitions, its stained glass smashed, its library books destroyed, and after 1647 its bell tower would be torn down. Washington marched his men out of the city at the head of his own regiment, William Russell's regiment, and the remains of Sandys's, to Rainbow Hill where Rainsborough waited.

What followed was an occupation conducted as if the city were a foreign capital. On 24 July Rainsborough ordered all Worcester citizens to surrender their arms on pain of death, Royalist soldiers to leave within ten days, and no Royalist to wear a sword inside the walls. The next day a Parliamentary committee began inventorying all estates and demanding a 25% contribution. Anyone they chose to designate a "delinquent" was, in the contemporary phrase, "then so squeezed that he could not recover in an age." The surrender articles had guaranteed the garrison the right to leave with personal arms and property; Major-General Massey's cavalry plundered them anyway. Fairfax himself wrote to the Speaker of the House of Commons that Massey's men had committed "a most dishonourable breach upon the articles of Worcester." The regiment was eventually disbanded. The First English Civil War, in the Midlands at least, was over. Five years later Worcester would be the site of one more battle - the final defeat of Charles II at the Battle of Worcester on 3 September 1651 - after which the city would suffer all of it again.